This invention relates to archery bows and, in particular, to a laterally adjustable limb pocket for an archery bow.
Whether hunting or target shooting, an archer strives to develop a consistent form to achieve accuracy with each shot. Seen from above, an archer holding a bow at full draw forms a triangle. The arrow is one side of the triangle, extending from the archer's hand (or release mechanism) to the arrow rest, which is attached just above the grip. The archer's arm is the second side of the triangle, extending from the grip to the archer's shoulder, and the archer's torso is the third side of the triangle. The angle between the arm of the archer and the arrow depends on the archer's style, the draw length of the bow, and the size of the archer. Preferably, the centerline of the handle and the arrow lie in the plane of the drawn bowstring.
A modern archery bow is typically made in three sections: a central handle or riser and two separate limbs. The handle is typically made from alloys of aluminum or magnesium and a separate wood or plastic grip is attached at approximately the middle of the handle. At each end of the handle is a limb pocket, which can be part of the handle or a separate component. The butt end of a limb fits within the limb pocket, which surrounds the end of the limb on three sides and holds the limb in position relative to the handle. Preferably, the centerlines of the limbs are also in the plane of the drawn bowstring.
The components of a bow, while approximately the same from bow to bow, actually vary in size due to manufacturing tolerances. The variations can additively combine or cancel out. If, for example, the variations happen to additively combine, then the centerlines of the limbs may not be coplanar. For some applications, the misalignment may not be a problem. For competitive target shooting, one wants a bow as well aligned as possible for the most consistent possible shooting.
In addition to compensating for manufacturing tolerances, it has been found that moving the limbs laterally relative to the handle can be beneficial since the handle can be held rotated slightly even when the bow is drawn. In this configuration, the sides of the handle are not parallel to the plane of the drawn bow string or to the arrow. This can improve the archer's grip, permitting him to hold the bow while keeping his wrist straight, thereby improving the consistency of his shooting. Finally, since there are many conflicting theories on the proper set up for a bow, some archers obtain more consistent results with bows having seemingly unconventional alignments.
A "compound" bow includes wheels or pulleys attached at the free ends of the limbs to obtain a mechanical advantage in bending the bow. Because of the stiff limbs used in a compound bow, the forces on the handle can be considerable. The forces are further increased if the wheels are eccentrically mounted or cam shaped, which enables one to use a much higher maximum draw weight. The force of the bowstring acting on the end of a limb may not align with the centerline of the handle, e.g. because of the way the bowstring is wound on the wheels or because of a sideward force from using a finger release or a sideward force due to a cable guard pushing to one side the cable portions of the bowstring. The result is a force tending to move the limb from side to side as the bow is drawn and fired by an archer. Thus, the limb attachment must be substantial enough to resist these forces for the bow to perform consistently. An adjustable limb pocket must not go out of adjustment when the bow is drawn and fired.
In view of the foregoing, it is therefore an object of the invention to provide a laterally adjustable limb pocket for an archery bow.
A further object of the invention is to provide a limb pocket which rotates in a plane orthogonal to the plane of a drawn bowstring.
Another object of the invention is to provide a limb pocket which translates, i.e. moves from side to side without rotation, in a plane orthogonal to the plane of a drawn bowstring.
A further object of the invention is to provide a limb pocket which can be adjusted even when a bow is strung, i.e. the pocket is under load.
Another object of the invention is to provide a bow which can be held with the sides of the bow handle not parallel to the plane of the drawn bowstring.
Another object of the invention is to provide an adjustable limb pocket which does not go out of adjustment when the bow is drawn and fired.